Help with a question about Osmosis!

I'm having a difficult time with a question in my homework and I was just wondering if anyone would help me out.
The question is:
Road salt that has been accidentally spilled on grass often kills grass. Explain why this happens?

I think it is because the salt deprives the grass of getting water, so it shrivels up and dies. Does anyone know if I am on the right track? I would love to hear another imput.